The correct option is C 632518
Given, in a certain language MONKEY is coded as 632471 and GANGA is coded as 58258.
Here, the letter MON stands for the numbers 632.
G stands for 5, A stands for 8 and Y stands for 1.
Therefore, the word 'MONGYA' is coded as '632518'.
Hence, option (C) is the correct answer.